A ureter is a tubular passageway in a body that conveys urine from the kidney to the bladder. Urine is transported through the ureter under the influence of hydrostatic pressure assisted by contractions of muscles located within the walls (lining) of the ureter. A urological condition that some patients experience is ureteral blockage or obstruction. Some common causes of such blockage are the formation of tumors or abnormalities within the ureteral lining or the formation and passage of kidney stones.
Ureteral stents are medical devices designed to extend through the ureter and to facilitate drainage from a kidney to the bladder when the ureter becomes blocked or obstructed. Generally, these stents are made from small diameter tubing of a biocompatible plastic. Ureteral stents may have multiple side holes to enhance drainage and typically include retention hooks or coils extending from both the kidney (distal) and bladder (proximal) ends of the tubing to prevent the migration of the ureteral stent after placement within the ureter.